An agreement has been signed between St Mowden and landowner S&J Padfield, which will see the firms collaborate on developing a one million sq ft office and warehouse park.
The site will take up 58 acres at a location to the west of Brentwood, Essex, at the junction of the M25 and A127.
St Modwen said the location is set to become a major employment hub, offering hundreds of new jobs in the region.
Under the terms of the proposals, B1, B2 and B8 floorspace will be offered, including supporting amenities.
Tim Seddon, London and south-east regional director at St Modwen, said the location of the site means it will have a lot to offer, and could build a lasting legacy for Brentwood.
"It has enormous potential and we have every confidence that this will be a flagship project for St Modwen that will bring significant office, warehouse and factory employment to the area," he commented.